- Somatotropic Axis Regulation Unravels the Differential Effects of Nutritional and Environmental Factors in Growth Performance of Marine Farmed Fishes. [Review]
- FEFront Endocrinol (Lausanne) 2018; 9:687
- The Gh/Prl/Sl family has evolved differentially through evolution, resulting in varying relationships between the somatotropic axis and growth rates within and across fish species. This is due to a w…
The Gh/Prl/Sl family has evolved differentially through evolution, resulting in varying relationships between the somatotropic axis and growth rates within and across fish species. This is due to a wide range of endogenous and exogenous factors that make this association variable throughout season and life cycle, and the present minireview aims to better define the nutritional and environmental regulation of the endocrine growth cascade over precisely defined groups of fishes, focusing on Mediterranean farmed fishes. As a result, circulating Gh and Igf-i are revitalized as reliable growth markers, with a close association with growth rates of gilthead sea bream juveniles with deficiency signs in both macro- or micro-nutrients. This, together with other regulated responses, promotes the use of Gh and Igf-i as key performance indicators of growth, aerobic scope, and nutritional condition in gilthead sea bream. Moreover, the sirtuin-energy sensors might modulate the growth-promoting action of somatotropic axis. In this scenario, transcripts of igf-i and gh receptors mirror changes in plasma Gh and Igf-i levels, with the ghr-i/ghr-ii expression ratio mostly unaltered over season. However, this ratio is nutritionally regulated, and enriched plant-based diets or diets with specific nutrient deficiencies downregulate hepatic ghr-i, decreasing the ghr-i/ghr-ii ratio. The same trend, due to a ghr-ii increase, is found in skeletal muscle, whereas impaired growth during overwintering is related to increase in the ghr-i/ghr-ii and igf-ii/igf-i ratios in liver and skeletal muscle, respectively. Overall, expression of insulin receptors and igf receptors is less regulated, though the expression quotient is especially high in the liver and muscle of sea bream. Nutritional and environmental regulation of the full Igf binding protein 1-6 repertoire remains to be understood. However, tissue-specific expression profiling highlights an enhanced and nutritionally regulated expression of the igfbp-1/-2/-4 clade in liver, whereas the igfbp-3/-5/-6 clade is overexpressed and regulated in skeletal muscle. The somatotropic axis is, therefore, highly informative of a wide-range of growth-disturbing and stressful stimuli, and multivariate analysis supports its use as a reliable toolset for the assessment of growth potentiality and nutrient deficiencies and requirements, especially in combination with selected panels of other nutritionally regulated metabolic biomarkers.
- Parasite Sensing of Host Nutrients and Environmental Cues. [Review]
- CHCell Host Microbe 2018 06 13; 23(6):749-758
- Parasites undergo complex life cycles that comprise a wide variety of cellular differentiation events in different host compartments and transmission across multiple hosts. As parasites depend on hos…
Parasites undergo complex life cycles that comprise a wide variety of cellular differentiation events in different host compartments and transmission across multiple hosts. As parasites depend on host resources, it is not surprising they have developed efficient mechanisms to sense alterations and adapt to the available resources in a wide range of environments. Here we provide an overview of the nutritional needs of different parasites throughout their diverse life stages and highlight recent insights into strategies that both hosts and parasites have developed to meet these nutritional requirements needed for defense, survival, and replication. These studies will provide the foundation for a systems-level understanding of host-parasite interactions, which will require the integration of molecular, epidemiologic, and mechanistic data and the application of interdisciplinary approaches to model parasite regulatory networks that are triggered by alterations in host resources.
- Vegetarian diets across the lifecycle: impact on zinc intake and status. [Review]
- AFAdv Food Nutr Res 2015; 74:93-131
- Optimal zinc status is an important consideration when evaluating the nutritional adequacy of vegetarian diets. In the absence of animal tissue sources of zinc and with increased intake of inhibitors…
Optimal zinc status is an important consideration when evaluating the nutritional adequacy of vegetarian diets. In the absence of animal tissue sources of zinc and with increased intake of inhibitors of zinc absorption, phytic acid in particular, the bioavailability of zinc is thought to be lower from vegetarian as compared to omnivorous diets. The aim of this chapter is to review the research that examines the effects of vegetarian compared to omnivorous diets on zinc intake and zinc status in the elderly, adults, children, pregnancy, and lactation. A narrative review of the published literature was undertaken, focusing on observational studies in humans that reported zinc intake and biomarkers of zinc status at various stages of the life cycle. Compared to their respective nonvegetarian control groups, adult male and female vegetarians have lower dietary zinc intakes and serum zinc concentrations. However in the elderly, children, and in women during pregnancy and lactation, there is insufficient evidence to determine whether zinc intake and status are lower in vegetarians compared to omnivores. Inconsistencies in study findings reflect variations inherent in the definition of vegetarian diets, and in many instances compromised statistical power due to a small sample size. Improved methods for the assessment of zinc status are required to determine whether homeostatic responses are sufficient to maintain an adequate zinc status in vegetarians, particularly during times of increased requirement. Appropriate dietary advice to increase the zinc content and bioavailability of vegetarian diets throughout the life cycle is prudent.
- Fatty-acid preference changes during development in Drosophila melanogaster. [Journal Article]
- PlosPLoS One 2011; 6(10):e26899
- Fatty-acids (FAs) are required in the diet of many animals throughout their life. However, the mechanisms involved in the perception of and preferences for dietary saturated and unsaturated FAs (SFAs…
Fatty-acids (FAs) are required in the diet of many animals throughout their life. However, the mechanisms involved in the perception of and preferences for dietary saturated and unsaturated FAs (SFAs and UFAs, respectively) remain poorly explored, especially in insects. Using the model species Drosophila melanogaster, we measured the responses of wild-type larvae and adults to pure SFAs (14, 16, and 18 carbons) and UFAs (C18 with 1, 2, or 3 double-bonds). Individual and group behavioral tests revealed different preferences in larvae and adults. Larvae preferred UFAs whereas SFAs tended to induce both a strong aversion and a persistent aggregation behavior. Adults generally preferred SFAs, and laid more eggs and had a longer life span when ingesting these substances as compared to UFAs. Our data suggest that insects can discriminate long-chain dietary FAs. The developmental change in preference shown by this species might reflect functional variation in use of FAs or stage-specific nutritional requirements, and may be fundamental for insect use of these major dietary components.
- Endogenous modification of macronutrient selection pattern in sea bass (Dicentrarchus labrax, L.). [Journal Article]
- PBPhysiol Behav 2008 Sep 03; 95(1-2):32-5
- The use of a single diet with a well defined composition to feed fish throughout their life cycle is an oversimplification that probably does not respond to their metabolic requirements. For example,…
The use of a single diet with a well defined composition to feed fish throughout their life cycle is an oversimplification that probably does not respond to their metabolic requirements. For example, the seasonal reproduction that characterizes most fish species demands changes in nutritional requirements. Bearing this in mind, the macronutrient selection pattern was studied from January to August in twelve individually housed sea bass exposed to a constant photoperiod (12L:12D h) and temperature (23+/-0.5 degrees C). The endogenous "seasonal" effect on food and energy intake regulation and macronutrient selection was determined, using protein (P), carbohydrate (CH), and fat (F) packaged separately into gelatine capsules, a method that prevents the diet chemosensory properties at oropharyngeal level from interfering with macronutrient selection. Energy intake changed monthly, the highest values being recorded in May and June and the lowest values in March and April. The preliminary results illustrated "seasonal" changes in the sea bass macronutrient selection pattern with, which showed a predominantly proteinic selection during April (53% P, 21% CH, 25% F) and lipidic in July (35% P, 19% CH, 42% F); the increase in fat selection from May to July being statistically significant. This is the first evidence supporting the existence of an endogenous rhythm in the "seasonal" energy regulation and macronutrient selection in fish through post-ingestive mechanisms and probably involving chemosensory detection in the gut and/or post-absorptive mechanisms, although the exact mechanisms involved have yet to be clarified.
- Importance of calcium, vitamin D and vitamin K for osteoporosis prevention and treatment. [Review]
- PNProc Nutr Soc 2008; 67(2):163-76
- Throughout the life cycle the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed on them exceed the ability of the bone t…
Throughout the life cycle the skeleton requires optimum development and maintenance of its integrity to prevent fracture. Bones break because the loads placed on them exceed the ability of the bone to absorb the energy involved. It is now estimated that one in three women and one in twelve men aged >55 years will suffer from osteoporosis in their lifetime and at a cost in the UK of > 1.7 pounds x 10(9) per year. The pathogenesis of osteoporosis is multifactorial. Both the development of peak bone mass and the rate of bone loss are determined by key endogenous and exogenous factors. Ca supplements appear to be effective in reducing bone loss in women late post menopause (>5 years post menopause), particularly in those with low habitual Ca intake (<400 mg/d). In women early post menopause (<5 years post menopause) who are not vitamin D deficient, Ca supplementation has little effect on bone mineral density. However, supplementation with vitamin D and Ca has been shown to reduce fracture rates in the institutionalised elderly, but there remains controversy as to whether supplementation is effective in reducing fracture in free-living populations. Re-defining vitamin D requirements in the UK is needed since there is evidence of extensive hypovitaminosis D in the UK. Low vitamin D status is associated with an increased risk of falling and a variety of other health outcomes and is an area that requires urgent attention. The role of other micronutrients on bone remains to be fully defined, although there are promising data in the literature for a clear link between vitamin K nutrition and skeletal integrity, including fracture reduction.
- Human nutrition and genetic variation. [Review]
- FNFood Nutr Bull 2007; 28(1 Suppl International):S101-15
- Human genetic variation is a determinant of nutrient efficacy and of tolerances and intolerances and has the potential to influence nutrient intake values (NIVs). Knowledge derived from the comprehen…
Human genetic variation is a determinant of nutrient efficacy and of tolerances and intolerances and has the potential to influence nutrient intake values (NIVs). Knowledge derived from the comprehensive identification of human genetic variation offers the potential to predict the physiological and pathological consequences of individual genetic differences and prevent and/or manage adverse outcomes through diet. Nutrients and genomes interact reciprocally; genomes confer differences in nutrient utilization, whereas nutrients effectively modify genome expression, stability, and viability. Understanding the interactions that occur among human genes, including all genetic variants thereof, and environmental exposures is enabling the development of genotype-specific nutritional regimens that prevent disease and promote wellness for individuals and populations throughout the life cycle. Genomic technologies may provide new criteria for establishing NIVs. The impact of a gene variant on NIVs will be dependent on its penetrance and prevalence within a population. Recent experiences indicate that few gene variants are anticipated to be sufficiently penetrant to affect average requirement (AR) values to a greater degree than environmental factors. If highly penetrant gene variants are identified that affect nutrient requirements, the prevalence of the variant in that country or region will determine the feasibility and necessity of deriving more than one AR or upper limit (UL) for affected genetic subgroups.
- Subcutaneous fat in normal and diseased states 3. Adipogenesis: from stem cell to fat cell. [Review]
- JAJ Am Acad Dermatol 2007; 56(3):472-92
- The quest for effective strategies to treat obesity has propelled fat research into an exploration of the molecular processes that drive adipocyte formation, and hence body fat mass. The development …
The quest for effective strategies to treat obesity has propelled fat research into an exploration of the molecular processes that drive adipocyte formation, and hence body fat mass. The development of obesity is dependent on the coordinated interplay of adipocyte hypertrophy (increased fat cell size), adipocyte hyperplasia (increased fat cell number), and angiogenesis. Evidence suggests that adipocyte hyperplasia, or adipogenesis, occurs throughout life, both in response to normal cell turnover as well as in response to the need for additional fat mass stores that arises when caloric intake exceeds nutritional requirements. Adipogenesis involves two major events-the recruitment and proliferation of adipocyte precursor cells, called preadipocytes, followed by the subsequent conversion of preadipocytes, or differentiation, into mature fat cells. In vitro studies using experimental and primary preadipocyte cell lines have uncovered the mechanisms that drive the adipogenic process, a tightly controlled sequence of events guided by the strict temporal regulation of multiple inhibitory and stimulatory signaling events involving regulators of cell-cycle functions and differentiation factors. This article reviews the current understanding of adipogenesis with emphasis on the various stages of adipocyte development; on key hormonal, nutritional, paracrine, and neuronal control signals; as well as on the components involved in cell-cell or cell-matrix interactions that are pivotal in regulating fat cell formation. Special consideration is given to clinical applications derived from adipogenesis research with impact on medical, surgical and cosmetic fields.
- Virulence of Corynosoma constrictum (Acanthocephala: Polymorphidae) in Hyalella azteca (Amphipoda) throughout parasite ontogeny. [Journal Article]
- JPJ Parasitol 2006; 92(4):749-55
- Development and growth of parasites depend on resources provided by the host and the parasite's ability to use them. Identifying specific costs incurred by the host provides insight for assessment of…
Development and growth of parasites depend on resources provided by the host and the parasite's ability to use them. Identifying specific costs incurred by the host provides insight for assessment of parasite energy budgets, which differ among taxa and ontogenetic stages. Data from this study were analyzed using an accelerated failure-time model with intensity as a covariate. Results indicated significantly reduced survival of amphipods, Hyalella azteca, infected with the acanthocephalan Corynosoma constrictum compared with uninfected controls. Male and female amphipod survivorship and infection intensity did not differ; however, amphipods with high-intensity infections (> 16 larvae) died earlier compared with amphipods with low-intensity infections (< 3 larvae). The majority of infected amphipods died between 12 and 24 days postexposure, a period of rapid larval development. It is hypothesized that host death may be due either to an increase in overall larval nutritional demands or to parasite-mediated depletion of a specific host substance. Results from this study suggest that developing C. constrictum satisfies energy requirements by depriving amphipod hosts of resources normally used for somatic growth and maintenance.
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- Amino acid requirements of infants and children. [Review]
- NNNestle Nutr Workshop Ser Pediatr Program 2006; 58:109-16; discussion 116-9
- Nitrogen balances have been conducted in preterm infants, preschool children, and 6- to 10-year-old children to determine dietary indispensable amino acid. A recent review concluded that the data, be…
Nitrogen balances have been conducted in preterm infants, preschool children, and 6- to 10-year-old children to determine dietary indispensable amino acid. A recent review concluded that the data, being sufficiently uncertain, could not be used as the basis for defining amino acid requirements in infants and children. Therefore, it was decided to use a factorial approach (basal plus growth). This approach is based on the assumption that basal requirements are the same throughout the life cycle. Recently, using indicator oxidation, the requirements of the eight classical indispensable amino acids have been defined in adults. These values have been used as the basal component of requirement in childhood. The growth component was based on the changes in body protein with age. We have recently shown that the maintenance requirements for branched chain amino acids are similar in children and adults, thereby validating the factorial approach.